Systems for LVAD operation during communication losses

ABSTRACT

Systems and devices for an adaptable blood pump are disclosed herein. The blood pump can be part of a mechanical circulatory support system that can include a system controller and the blood pump. The blood pump can include a rotary motor and a control unit that can communicate with the system controller. The blood pump can determine when communication with the system controller is established or has been lost. The blood pump can retrieve one or several back-up parameters when communication with the system controller has been lost, and can operate according to these back-up parameters.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/687,817, filed Apr. 15, 2015, which application claims the benefit ofU.S. Provisional Application No. 61/979.803 filed Apr. 15, 2014, theentire contents of which are hereby incorporated by reference in theirentirety for all purposes.

BACKGROUND

This application relates generally to mechanical circulatory supportsystems, and more specifically relates to control systems, for animplantable blood pump.

Ventricular assist devices, known as VADs, are implantable blood pumpsused for both short-term (i.e., days, months) and long-term applications(i.e., years or a lifetime) where a pattern's heart is incapable ofproviding adequate circulation, commonly referred to as heart failure orcongestive heart failure. According to the American Heart Association,more than five million Americans are living with heart failure, withabout 670,000 new cases diagnosed every ear. People with heart failureoften have shortness of breath and fatigue. Years of living with blockedarteries or high blood pressure can leave your heart too weak to pumpenough blood to your body. As symptoms worsen, advanced heart failuredevelops.

A patient suffering from heart failure, also called congestive heartfailure, may use a VAD while awaiting a heart transplant or as a longterm destination therapy. In another example, a patient may use a VADwhile recovering from heart surgery. Thus, a VAD can supplement a weakheart (i.e., partial support) or can effectively replace the naturalheart's function. VADs can be implanted in the patient's body andpowered by an electrical power source inside or outside the patient'sbody.

As VAD systems continue to develop and are more widely used, theimportance of reliability continues to increase. Reliability becomeparticularly significant in light of the mechanical and electricalcomplexity of the VAD, and the interrelation and communication betweenthe different components working with the VAD. Thus, new methods,systems, and devices that will increase the reliability of the VAD aredesired.

BRIEF SUMMARY

The present invention provides new systems, methods, and devices whichcan advantageously allow for uninterrupted operation of pump componentsof the VAD without the receipt of external control signals during acommunication loss or interruption. For example, the pump components ofthe VAD can be separately located from a portion of the system controlsof the VAD. This can advantageously increase the implantability of thepump components by decreasing the size of the housing containing thepump components. When the pump components of the VAD are separatelyhoused from a portion of the system controls, the pump components of theVAD can receive control signals from the system controls that direct theoperation of the pump components. In the event that these controlsignals are not received, the pump components of the VAD can operateaccording to one or several back-up parameters. This is clearlyadvantageous from the patient's perspective as this decreases the riskof a failure of the VAD due to, for example, interference withcommunications or a failure of the system controls. Thus, thiscapability increases the robustness and reliability of the VAD and inturn increases patient safety and clinical effectiveness.

One aspect of the present disclosure relates to a mechanical circulatorysupport system. The mechanical circulatory support system includes acontroller that can generate control signals including at least oneperformance parameter and that can repeatingly transmit the controlsignals within consecutive time periods, and an implantable blood pumpcommunicatively coupled to the controller. The blood pump can include arotary motor and a control unit communicatively coupled with the rotarymotor. The control unit can track the consecutive time periods, receivethe control signals from the controller, and retrieve at least onebackup parameter if a control signal is not received from the controllerwithin a predetermined time period or within a number of the consecutivetime periods. In some embodiments, this can ensure operation of theimplantable blood pump during a communication interruption or loss.

In some embodiments of the mechanical circulatory support system, thecontrol unit can control at least one of the motion and position of therotary motor, and specifically, the control unit can control at leastone of the speed, mode, or pulse parameter of the motor according to thereceived control signals or the at least one backup parameter. In someembodiments, the control unit can determine a current pump performance,compare the current pump performance to the at least one back-upparameter, and generate one or several control signals to achieve thepump performance specified by the at least one back-up parameter. Insome embodiments, the predetermined time period can be at least 5seconds. In some embodiments, one of the consecutive time periods canhave a length of time of less than 1 second. In some embodiments, thepredetermined number can be at least five consecutive time periods.

In some embodiments of the mechanical circulatory support system, the atleast one performance parameter can include at least one of a pumpspeed, a pump operational mode, and a pulse parameter. In someembodiments, the pulse parameter can be one of a pulse duration, asystolic pressure, a diastolic pressure, and a pulse pressure. In someembodiments, the pump operational mode can be at least one of continuousflow, pulsatile pumping, or non-pulsatile mode. In some embodiments, theat least one back-up parameter can be at least one of a pump speed, pumpoperational mode, and a pulse parameter, and in some embodiments, thecontrol unit can generate the at least one back-up parameter from thecontrol signal received from the controller. In some embodiments, thecontrol unit can include memory which can store the at least one back upparameter.

In some embodiments of the mechanical circulatory support system, thecontrol unit, can return to operation based on control signals receivedfrom the external controller when communication is re-established. Insome embodiments, the controller can include an external or implantablecontroller configured to wirelessly transmit the control signals. Insome embodiments, the controller can include an external or implantablecontroller having to driveline coupled to the implantable pump totransmit the control signals. In some embodiments, the control unit cancontrol the mode of the rotary motor according to the received controlsignals or the at least one back-up parameter, and in some embodiments,the control unit can control the pulse parameter of the rotary motoraccording to the received control signals or the at least one back-upparameter.

One aspect of the present disclosure relates to an implantable bloodpump. The implantable blood pump can include a rotary motor, and acontrol unit communicatively coupled with the rotary motor. The controlunit can repeatingly receive control signals that can include at leastone performance parameter, track receipt of the control signals over atime period, and retrieve at least one back-up parameter if a controlsignal is not received within a predetermined time period to ensureoperation of the implantable blood pump during a communicationinterruption or loss.

in some embodiments of the implantable blood pump, the control unit canprovide a status update in response to a received control signal. Insome embodiments, the at least one back-up parameter is retrieved if acontrol signal is not received within the predetermined time period offive seconds. In some embodiments, the at least one performanceparameter can include at least one of a pump speed, a pump operationalmode, and a pulse parameter. In some embodiments, the pulse parametercan be one of a pulse duration, a systolic pressure, a diastolicpressure, and a pulse pressure, and in some embodiments, the pumpoperational mode can include at least one of continuous flow, pulsatilepumping, or non-pulsatile mode.

In some embodiments of the implantable blood pump, the at least oneback-up parameter can include at least one of a pump speed, a pumpoperational mode, and a pulse parameter. In some embodiments, thecontrol unit can return to operation based on control signals receivedfrom the controller when a new control signal is received. In someembodiments, the rotary motor can be located within a first implantable,housing and the control unit can be located in a second implantablehousing.

One aspect of the present disclosure relates to a method of operating animplantable blood pump. The method includes repeatedly receiving acontrol signal that includes at least one blood pump performanceparameter, operating the blood pump according to the control signal,triggering a threshold indicating absence of receipt of a new controlsignal, retrieving at least one back-up parameter that includes a bloodpump performance parameter, and operating the blood pump according tothe at least one back-up parameter.

In some embodiments of the method, the at least one back-up parametercan be retrieved from memory located on the blood pump. In someembodiments, the threshold can be triggered when a new control signal isnot received within a predetermined time period. In some embodiments,the predetermined time period can be at least 5 seconds. In someembodiments, the blood pump performance parameter can include a firstportion, specifying a pump speed, and a second portion specifying apulse parameter. In some embodiments, the method includes storing lirefirst portion of the control signal as the at least one back-upparameter. In some embodiments, the method includes receiving a secondcontrol signal when the blood pump is operating according to the atleast one back-up parameter, and operating the blood pump according tothe second control signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a mechanical circulatory support systemimplanted in a patient's body.

FIG. 2 is an exploded view of certain components of the circulatorysupport system that are implanted in a patient's body.

FIG. 3 is an illustration of a blood pump in an operational positionimplanted or a patient's body.

FIG. 4 is a cross-sectional view of the blood pump of FIG. 3.

FIG. 5 is a partial cut-away perspective view of a stator of a bloodpump.

FIG. 6 is a schematic diagram clan overall communication architecture ofthe mechanical support system of FIG. 1.

FIG. 7 is a schematic diagram illustrating one embodiment of a bloodpump.

FIG. 8 is a flowchart illustrating one embodiment of operation of theblood pump.

FIG. 9 is a schematic illustration of some of the operations of theblood pump.

FIG. 10 is a flowchart illustrating one embodiment of a process foroperation of the blood pump when communication with a system controlleris lost.

FIG. 11 is a flowchart illustrating one embodiment of process forgenerating a back-up parameter.

DETAILED DESCRIPTION

FIG. 1 is an illustration of a mechanical circulatory support system 10implanted in a patient's body 12. The mechanical circulatory supportsystem 10 comprises a implantable blood pump 14, ventricular cuff 16,outflow cannula 18, system controller 20, and power sources 22, theimplantable blood pump 14 may comprise a VAD that is attached to an atof the left ventricle, as illustrated, or the right ventricle, or bothventricles of the heart 24. The VAD may comprise a centrifugal (asshown) or axial flow pump as described in further detail herein that iscapable of pumping the entire output delivered to the left ventriclefrom the pulmonary circulation (i.e., up to 10 liters per minute).Related blood pumps applicable to the present invention are described ingreater detail below and in U.S. Pat. Nos. 5,695,471, 6,071,093,6,116,862, 6,186,665, 6,234,772, 6,264,635, 6,688,861, 7,699,586,7,976,271, 7,997,854, 8,007,254, 8,152,493, 8,652,024, and 8,668,473 andU.S. Patent Publication Nos. 2007/0078293, 2008/0021394, 2009/0203957,2012/0046514, 2012/0095281, 2013/0096364, 2013/0170970, 2013/0121821,and 2013/0225909, all of which are incorporated herein by reference forall purposes in their entirety. With reference to FIGS. 1 and 2, theblood pump 14 may be attached to the heart 24 via the ventricular cuff16 which is sewn to the heart 24 and coupled to the blood pump 14. Theother end of the blood pump 14 connects to the ascending aorta via theoutflow cannula 18 so that the VAD effectively diverts blood from theweakened ventricle and propels it to the aorta for circulation to therest of the patient's vascular system.

FIG. 1 illustrates the mechanical circulatory support system 10 duringbattery 22 powered operation. A driveline 26 which exits through thepatient's abdomen 28, connects the implanted blood pump 14 to the systemcontroller 20, which monitors system 10 operation. Related controllersystems applicable to the present invention are described in greaterdetail below and in U.S. Pat. Nos. 5,888,242, 6,991,595, 8,323,174,8,449,444, 8,506,471, 8,597,350, and 8,657,733 and U.S. PatentPublication Nos. 2005/0071001 and 2013/0314047, all of which areincorporated herein by reference for all purposes in their entirety. Thesystem may be powered by either one, two, or more batteries 22. It willbe appreciated that although the system controller 20 and power source22 are illustrated outside/external to the patient body, the driveline26, system controller 20 and/or power source 22 may be partially orfully implantable within the patient, as separate components orintegrated with the blood bump 14. Examples of such modifications arefurther described in U.S. Pat. No. 8,562,508 and U.S. Patent PublicationNo. 2013/0127253, all of which are incorporated herein by reference forall purposes in their entirety.

With reference to FIGS. 3 to 5, a left ventricular assist blood pump 100having a circular shaped housing 110 is implanted in a patient's bodywith a first face 111 of the housing 110 positioned against thepatient's heart H and a second face 113 of the housing 110 facing awayfrom the heart H. The first face 111 of the housing 110 includes aninlet cannula 112 extending into the left ventricle LV of the heart H.The second face 113 of the housing 110 has a chamfered edge 114 to avoidirritating other tissue that may come into contact with the blood pump100, such as the patient's diaphragm. To construct the illustrated shapeof the puck-shaped housing 110 in a compact form, a stator 120 andelectronics 130 of the pump 100 are positioned on the inflow side of thehousing toward first face 111, and a rotor 140 of the pump 100 ispositioned along the second face 113. This positioning of the stator120, electronics 130, and rotor 140 permits the edge 114 to be chamferedalong the contour of the rotor 140, as illustrated in at least FIGS.2-4, for example.

Referring to FIG. 4, the blood pump 100 includes a dividing wall 115within the housing 110 defining a blood flow conduit 103. The blood flowconduit 103 extends from an inlet opening 101 of the inlet cannula 112through the stator 120 to an outlet opening 105 defined by the housing110. The rotor 140 is positioned within the blood flow conduit 103. Thestator 120 is disposed circumferentially about a first portion 140 a ofthe rotor 140, for example about a permanent magnet 141. The stator 120is also positioned relative to the rotor 140 such that, in use, bloodflows within the blood flow conduit 103 through the stator 120 beforereaching the rotor 140. The permanent magnet 141 has a permanentmagnetic north pole N and a permanent magnetic south pole S for combinedactive and passive magnetic levitation of the rotor 140 and for rotationof the rotor 140. The rotor 140 also has a second portion 140 b thatincludes impeller blades 143. The impeller blades 143 are located withina volute 107 of the blood flow conduit such that the impeller blades 143are located proximate to the second face 113 of the housing 110.

100311 The puck shaped housing 110 further includes a peripheral wall116 that extends between the first face 111 and a removable cap 118. Asillustrated, the peripheral wall 116 is formed as a hollow circularcylinder having a width W between opposing portions of the peripheralwall 116. The housing 110 also has a thickness T between the first face111 and the second face 113 that is less than the width W. The thicknessT is from about 0.5 inches to about 1.5 inches, and the width W is fromabout 1 inch to about 4 inches. For example, the width W can beapproximately 2 inches, and the thickness T can be approximately 1 inch.

The peripheral wall 116 encloses an internal compartment 117 thatsurrounds the dividing wall 115 and the blood flow conduit 103, with thestator 120 and the electronics 130 disposed in the internal compartment117 about the dividing wall 115. The removable cap 118 includes thesecond face 113, the chamfered edge 114, and defines the outlet opening105. The cap 118 can be threadedly engaged with the peripheral wall 116to seal the cap 118 in engagement with the peripheral wall 116. The cap118 includes an inner surface 118 a of the cap 118 that defines thevolute 107 that is in fluid communication with the outlet opening 105.

Within the internal compartment 117, the electronics 130 are positionedadjacent to the first face 111 and the stator 120 is positioned adjacentto the electronics 130 on an opposite side of the electronics 130 fromthe first face 111. The electronics 130 include circuit boards 131 andvarious components carried on the circuit boards 131 to control theoperation of the pump 100 (e.g., magnetic levitation and/or drive of therotor) by controlling the electrical supply to the stator 120. Thehousing 110 is configured to receive the circuit boards 131 within theinternal compartment 117 generally parallel to the first face 111 forefficient use of the space within the internal compartment 117. Thecircuit boards also extend radially-inward towards the dividing wall 115and radially-outward towards the peripheral wall 116. For example, theinternal compartment 117 is generally sized no larger than necessary toaccommodate the circuit boards 131, and space for heat dissipation,material expansion, potting materials, and/or other elements used ininstalling the circuit hoards 131. Thus, the external shape of thehousing 110 proximate the first face 111 generally fits the shape of thecircuits boards 131 closely to provide external dimensions that are notmuch greater than the dimensions of the circuit hoards 131.

With continued reference to FIGS. 4 and 5, the stator 120 includes aback iron 121 and pole pieces 123 a-123 f arranged at intervals aroundthe dividing wall 115. The back iron 121 extends around the dividingwall 115 and is formed as a generally flat disc of a ferromagneticmaterial, such as steel, in order to conduct magnetic flux. The backiron 121 is arranged beside the control electronics 130 and provides abase for the pole pieces 123 a-123 f.

Each of the pole piece 123 a-123 f is L-shaped and has a drive coil 125for generating an electromagnetic field to rotate the rotor 140. Forexample, the pole piece 123 a has a first leg 124 a that contacts theback iron 121 and extends from the back iron 121 towards the second face113. The pole piece 123 a may also have a second leg 124 b that extendsfrom the first leg 124 a through an opening of a circuit board 131towards the dividing wall 115 proximate location of the permanent magnet141 of the rotor 140. In an aspect, each of the second legs 124 b of thepole pieces 123 a-123 f is sticking through an opening of the circuitboard 131. In an aspect, each of the first legs 124 a of the pole pieces123 a-123 f is sticking through an opening of the circuit board 131. Inan aspect, the openings of the circuit board are enclosing the firstlegs 124 a of the pole pieces 123 a-123 f.

In a general aspect, the implantable blood pump 100 may include a Hallsensor that may provide an output voltage, which is directlyproportional to a strength of a magnetic field that is located inbetween at least one of the pole pieces 123 a-123 f and the permanentmagnet 141, and the output voltage may provide feedback to the controlelectronics 130 of the pump 100 to determine if the rotor 140 and/or thepermanent magnet 141 is not at its intended position for the operationof the pump 100. For example, a position of the rotor 140 and/or thepermanent magnet 141 may be adjusted, e.g. the rotor 140 or thepermanent magnet 141 may be pushed or pulled towards a center of theblood flow conduit 103 or towards a center of the stator 120.

Each of the pole pieces 123 a-123 f also has a levitation coil 127 forgenerating an electromagnetic field to control the radial position ofthe rotor 140. Each of the drive coils 125 and the levitation coils 127includes multiple windings of a conductor and the pole pieces 123 a-123f. Particularly, each of the drive coils 125 is wound around twoadjacent ones of the pole pieces 123, such as pole pieces 123 d and 123e, and each levitation coil 127 is wound around a single pole piece. Thedrive coils and the levitation coils 127 are wound around the first legsof the pole pieces 123, and magnetic flux generated by passingelectrical current though the coils 125 and 127 during use is conductedthrough the first legs and the second 127 legs of the pole pieces 123and the back iron 121. The drive coils 125 and the levitation coils 127of the stator 120 are arranged in opposing pairs and are controlled todrive the rotor and to radially Levitate the rotor 140 by generatingelectromagnetic fields that interact with the permanent magnetic poles Sand N of the permanent magnet 141. Because the stator 120 includes boththe drive coils 125 and the levitation coils 127, only a single statoris needed to levitate the rotor 140 using only passive and activemagnetic forces, The permanent magnet 141 in this configuration has onlyone magnetic moment and is formed from a monolithic permanent magneticbody 141. For example, the stator 120 can be controlled as discussed inU.S. Pat. No. 6,351,048, the entire contents of which are incorporatedherein by reference for all purposes. The control electronics 130 andthe stator 120 receive electrical power from a remote power supply via acable 119 (FIG. 3). Further related patents, namely U.S. Pat. Nos.5,708,346, 6,053,705, 6,100,618, 6,222,290, 6,249,067, 6,378,251,6,351,048, 6,355,998, 6,634,224, 6,879,074, and 7,112,903, all of whichare incorporated herein by reference for all purposes in their entirety.

The rotor 140 is arranged within the, housing 110 such that itspermanent magnet 141 is located upstream of impeller blades in alocation closer to the inlet opening 101. The permanent magnet 141 isreceived within the blood flow conduit 103 proximate the second legs 124b of the pole pieces 123 to provide the passive axial centering forcethough interaction of the permanent magnet 141 and ferromagneticmaterial of the pole pieces 123. The permanent magnet 141 of the rotor140 and the dividing wall 115 form a gap 108 between the permanentmagnet 141 and the dividing wall 115 when the rotor 140 is centeredwithin the dividing wall 115. The gap 108 may be from about 0.2millimeters to about 2 millimeters. For example, the gap 108 isapproximately 1 millimeter. The north permanent magnetic pole N and thesouth permanent magnetic pole S of the permanent magnet 141 provide apermanent magnetic attractive force between the rotor 140 and the stator120 that acts as a passive axial centering force that tends to maintainthe rotor 140 generally centered within the stator 120 and tends toresist the rotor 140 from moving towards, the first lace 111 or towardsthe second face 113. When he gap 108 is smaller, the magnetic attractiveforce between the permanent magnet 141 and the stator 120 is greater,and the gap 108 is sized to allow the permanent magnet 141 to providethe passive magnetic axial centering force having a magnitude that isadequate to limit the rotor 140 from contacting the dividing wall 115 orthe inner surface 118 a of the cap 118. The rotor 140 also includes ashroud 145 that covers the ends of the impeller blades 143 facing thesecond face 113 that assists in directing blood flow into the volute107. The shroud 145 and the inner surface 118 a of the cap 118 form agap 109 between the shroud 145 and the inner surface 118 a when therotor 140 is levitated by the stator 120. The gap 109 is from about 0.2millimeters to about 2 millimeters. For example, the gap 109 isapproximately 1 millimeter.

As blood flows through the blood flow conduit 103, blood flows through acentral aperture 141 a formed through the permanent magnet 141. Bloodalso flows through the gap 108 between the rotor 140 and the dividingwall 115 and through the gap 109 between the shroud 145 and the innersurface 108 a of the cap 118. The gaps 108 and 109 are large enough toallow adequate blood flow to limit clot formation that may occur if theblood is allowed to become stagnant, The gaps 108 and 109 are also largeenough to limit pressure forces on the blood cells such that the bloodis not damaged when flowing through the pump 100. As a result of thesize of the gaps 108 and 109 limiting pressure forces on the bloodcells, the gaps 108 and 109 are too large to provide a meaningfulhydrodynamic suspension effect. That is to say, the blood does not actas a bearing within the gaps 108 and 109, and the rotor is onlymagnetically-levitated. In various embodiments, the gaps 108 and 109 aresized and dimensioned so the blood flowing through the gaps forms a filmthat provides a hydrodynamic suspension effect. In this manner, therotor can be suspended by magnetic forces, hydrodynamic forces, or both.

Because the rotor 140 is radially suspended by active control of thelevitation cods 127 as discussed above, and because the rotor 140 isaxially suspended by passive interaction of the permanent magnet 141 andthe stator 120, no rotor levitation components are needed proximate thesecond face 113. The incorporation of all the components for rotorlevitation in the stator 120 (i.e., the levitation coils 127 and thepole pieces 123) allows the cap 118 to be contoured to the shape of theimpeller blades 143 and the volute 107. Additionally, incorporation ofall the rotor levitation components in the stator 120 eliminates theneed for electrical connectors extending from the compartment 117 to thecap 118, which allows the cap to be easily installed and/or removed andeliminates potential sources of pump failure.

In use, the drive coils 125 of the stator 120 generates electromagneticfields through the pole pieces 123 that selectively attract and repelthe magnetic north pole N and the magnetic south pole S of the rotor 140to cause the rotor 140 to rotate within stator 120. For example, theHall sensor may sense a current position of the rotor 140 and/or thepermanent magnet 141, wherein the output voltage of the Hall sensor maybe used to selectively attract and repel the magnetic north pole N andthe magnetic south pole S of the rotor 140 to cause the rotor 140 torotate within stator 120. As the rotor 140 rotates, the impeller blades143 force blood into the volute 107 such that blood is forced out of theoutlet opening 105. Additionally, the rotor draws, blood into pump 100through the inlet opening 101. As blood is drawn into the blood pump byrotation of the impeller blades 143 of the rotor 140, the blood flowsthrough the inlet opening 101 and flows through the control electronics130 and the stator 120 toward the rotor 140. Blood flows through theaperture 141 a of the permanent magnet 141 and between the impellerblades 143, the shroud 145, and the permanent magnet 141, and into thevolute 107. Blood also flows around the rotor 140, through the gap 108and through the gap 109 between the shroud 145 and the inner surface 118a of the cap 118. The blood exits the volute 107 through the outletopening 105, which may be coupled to an outflow cannula.

FIG. 6 is a schematic diagram of an overall communication architectureof the mechanical support system of FIG. 1. A driveline couples theimplanted blood pump 100 to the system controller 20, which monitorssystem operation via various software applications. The blood pump 100itself also includes several software applications that are executableby the on board electronics 130 (e.g., processors) for variousfunctions, such as to control radial levitation and/or drive of therotor of the pump 100 during operation. The system controller 20 may inturn be coupled to batteries 22 or a power module 30 that connect to anAC electrical outlet. The system controller 20 may also include anemergency backup battery (EBB) to power the system (e.g., when thebatteries 22 are depleted) and a membrane overlay, including bluetoothcapabilities for wireless data communication. An external computerhaving a system monitor 32 that is configurable by an operator, such asclinician or patient, may further be coupled to the circulatory supportsystem for configuring the system controller 20, implanted blood pump100, and/or patient parameters, updating software on the systemcontroller 20 and/or implanted blood pump 100, monitoring systemoperation, and/or as a conduit for system inputs or outputs.

In some embodiments, the software applications of the blood pump 100 caninclude, for example, an initial program loader (IPL), loader software,and/or application software. In some embodiments, the IPL can beconfigured to select and load one or several software applicationscorresponding, to one or several modes of operation of the blood pump100. In some embodiments, these, one or several modes of operation ofthe blood pump 100 can include an operation mode, a test mode, a faultmode, or the like. The selecting and loading of one or several softwareapplications corresponding to one or several modes of operation of theblood pump 100 can include, for example, selecting and loading one orseveral of the loader software and/or the application software. In someembodiments, the IPL can include information relating to one or severalfailsafe and/or fault protocols that can be used by the blood pump 100.Some of these failsafe and/or fault protocols will be discussed atlength below.

The loader software, can, in some embodiments, be configured to directthe operation of the blood pump 100 during the loading of one or severalsoftware applications onto the blood pump 100, These one or severalsoftware applications can include, for example, one or severalapplication softwares, one or several IPL applications, or the like. Insome embodiments, the loader software can prescribe one or severalprocesses for updating and/or loading one or several softwareapplications onto the blood pump 100. These processes and associatedfailsafes will be discussed in greater details below.

The application software can include one or several parameters fordirecting the pumping operation of the blood pump 100. In someembodiments, the application software can comprise one of a clinicalapplication software which can be configured to control the operation ofthe blood pump 100 when implanted in a patient, and in some embodiments,the application software can comprise a production software that can beconfigured to control the operation of the blood pump 100 duringproduction and/or testing of the blood pump 100.

In some embodiments, these parameters can specify a control or controlregimen for the position and/or motion of the rotor 140. For example,these parameters can specify the aspects of the levitation controland/or rotation control of the rotor 140.

In some embodiments, the parameters of the application software canspecify, for example a desired performance of the blood pump 100 and/orone or several desired performance parameters, such as, for example, adesired pump speed, and desired pumped flow rate, a pulse generation, orthe like. In some embodiments, these parameters can be actively used tocontrol the operation of the blood pump 100, and in some embodimentsthese parameters can be stored during normal operation of the blood pump100 and used as part of one or several failsafe and/or fault protocols.In some embodiments, the parameters of the application software canspecify the generation and/or collection of data from the blood pump 100and/or interfacing of the blood pump 100 to other components of themechanical circulatory support system 10.

In some embodiments, the application software can comprises a firstapplication software containing parameters relating to the currentoperation of the blood pump, and in some embodiments, the applicationsoftware can comprise a second application software containingparameters unrelated to the current operation of the blood pump 100. Inone embodiment, for example, the blood pump 100 can comprise the secondapplication software as a backup to the first application software. Insome embodiments, the first application software can be identical to thesecond application software, and in some embodiments, the firstapplication can be different than the second application software.

FIG. 7 is at schematic diagram illustrating one embodiment of the bloodpump 100. As seen in FIG. 7. the blood pump 100 includes electronics 130and a rotary motor 200, which rotary motor 200 call include the stator120 and the rotor 140. As seen in FIG. 7, the electronics 130 caninclude a control unit 202 that can control the operations of the bloodpump 100 and can interact with other components of the mechanicalcirculatory support system 10. As shown, the control unit 202 cancommunicate with the rotary motor 200 and with the communications module208. In some embodiments, the control unit 202 and electronics 130 canbe located in the same implantable housing 110 as the rotary motor 200,and in some embodiments, the control unit and electronics can be locatedin a separate implantable housing than the blood pump housing 110. Forexample, the system controller 20 can be located in an implantablehousing, and the control unit 202 and electronics 130 can be co-locatedin that same implantable housing in a fully implantable transcutaneousenergy transfer system.

The control unit 202 can, include a processor 204. The processor 204 canprovide instructions to, and receive information from the othercomponents of the blood pump 100 and/or from the other components of themechanical circulatory support system 10. The processor 204 can actaccording to stored instructions, which stored instructions can belocated in memory 206 associated with the processor 204 and/or in othercomponents of the blood pump 100 and/or of the mechanical circulatorysupport system 10. The processor 204 can comprise a microprocessor, suchas a microprocessor from Intel® or Advanced Micro Devices, Inc.®, or thelike.

In some embodiments, the stored instructions directing the operation ofthe processor 204 may be implemented by hardware, software, scriptinglanguages, firmware, middleware, microcode, hardware descriptionlanguages, and/or any combination thereof. When implemented in software,firmware, middleware, scripting, language, and/or microcode, the programcode or code segments to perform the necessary tasks may be stored in amachine readable medium such as a storage medium. A code segment ormachine-executable instruction may represent a procedure, a function, asubprogram, a program, a routine, a subroutine, a module, a softwarepackage, a script, a class, or any combination of instructions, datastructures, and/or program statements. A code segment may be coupled toanother code segment or a hardware circuit by passing and/or receivinginformation, data, arguments, parameters, and/or memory contents.Information, arguments, parameters, data, etc. may be passed, forwarded,or transmitted via any suitable means including memory sharing, messagepassing, token passing, network transmission, etc.

As seen in FIG. 7, the control unit 202 includes a memory 206. In thisembodiment, the memory 206 is the storage medium containing the storedinstructions. The memory 206 may represent one or more memories forstoring data, including read only memory (ROM), random access memory(RAM), magnetic RAM, core memory, magnetic disk storage mediums, opticalstorage mediums, flash memory devices and/or other machine readablemediums for storing information. In some embodiments, the memory 206 maybe implemented within the processor 204 or external to the processor204. In some embodiments, the memory 206 can be any type of long term,short term, volatile, nonvolatile, or other storage medium and is not tobe limited to any particular type of memory or number of memories, ortype of media upon which memory is stored. In some embodiments, thememory 206 can include, for example, one or both of volatile andnonvolatile memory. In one specific embodiment, the memory 206 caninclude a volatile portion such as RAM memory, and a nonvolatile portionsuch as flash memory.

In some embodiments, the memory 206 can be divided into one or severalpartitions. In one embodiment in which the memory 206 contains aplurality of software applications, the memory 206 can be divided into aplurality of partitions so as to be, for example, in a one to onerelationship with the number of software applications in the pluralityof software applications. In some embodiments, some or all of thesoftware applications stored in the memory 206 can be stored in a uniqueone of the partitions in the memory 206. In one embodiment in which thememory 206 comprises a volatile portion and a nonvolatile portion, thepartitions can be created in one or both of the volatile portion and thenonvolatile portion. Specifically, in one embodiment in which the memory206 comprises RAM and flash memory, the flash memory can be divided intoa plurality of partitions. In some embodiments, the plurality ofsoftware applications can be stored in the plurality of partitions inthe flash memory.

As described above, the processor 204 can send information and/orsignals with and/or receive information and/or signals from thecommunications module 208. The communications module 208 can includefeatures configured to send and receive information, including, forexample, an antenna, a transmitter, receiver, or any other feature thatcan send and receive information. The communications module 208 cancommunicate via a wired or wireless link with, for example, the systemcontroller 20 and/or the rotary motor 200. In some embodiments, thecommunications module 208 can communicate via cellular networks, WLANnetworks, or any other wireless network. In some embodiments, the bloodpump 100 can be configured to generate a signal in response to some orall communications received from in the system controller 20, and/or tonot generate a signal to the system controller 20 unless a signal fromthe system controller 20 has been first received by the blood pump 100.

FIG. 8 is a flow-chart illustrating one embodiment of a process 220 foroperation of the blood pump 100. The process 220 can be performed tostart the pumping of the blood pump 100, and can be performed usingcomponents of the blood pump 100 including, for example, the controlunit 202. The process 220 begins, in some embodiments, at block 222wherein the blood pump 100 is powered up. In some embodiments, thepowering up the blood pumped 100 can include the receipt of power by theblood pump 100 from one of the batteries 22 and/or other power source.In some embodiments, after the blood pump 100 is powered, the process220 proceeds to block 224 wherein the IPL is run. In some embodiments,the running of the IPL can include, for example, retrieval of the IPLfrom the memory 206 and the execution of IPL instructions by theprocessor 204.

After the IPL is running, the process 220 proceeds to block 226 whereinthe IPL selects one or several software applications for control of theblood pump 100. In some embodiments, the one or several softwareapplications can be selected from the memory 206. After the one orseveral software applications have been selected, the process 220proceeds to block 228 wherein the IPL determines the validity of the oneor several selected software applications. In some embodiments, this caninclude the determination of the functionality of the one or severalsoftware applications and/or the detection of any faults and/or errorsin, or caused one or several selected software applications.

After the IPL has determined the validity of the one or several selectedsoftware applications, the process 220 proceeds to block 210 wherein theIPL retrieves the one or sever selected software applications from thememory 206 and starts the one or several selected software applications.As specifically seen in FIG. 8, the IPL can, for example, and asdepicted in block 232, copy a software application stored in one of thepartitions of the memory 206, such as, for example, a second partitionin the flash memory, to the RAM and start the copied softwareapplication. Similarly, in one embodiment the IPL can, and as depictedin block 234, copy a software application stored in one of thepartitions of the memory, such as, for example, a third partition in theflash memory, to the RAM and start the copied software application. Insome embodiments, the starting of the software application stored in oneof the second partition and the third partition can result in thestarting of the blood pump 100, the starting of the movement of therotor 140, and the starting of the associated pumping of blood. In oneembodiment, the IPL can, as depicted in block 236, start the loadersoftware. In some embodiments, the loader software can be started as anearly step in the update of the blood pump 100.

FIG. 9 is a schematic illustration of one embodiment of memory 206 ofthe blood pump 100. As depicted in FIG. 9, the memory 206 of the bloodpump can include volatile memory, such as RAM 260 and non-volatilememory such as flash 202. The flash 262 can be divided into severalpartitions. In the embodiment depicted in FIG. 9, the flash 262 isdivided into partition 0 264-A, partition 1 264-B, partition 2 264-C,partition 3 264-D, partition 4 264-E, partition 5 264-F. As seen in FIG.9, some of the partitions 264-A-264-F contain a software application.Specifically, partition 0 264-A contains the IPL and loader software,partition 1 264-B contains a backup copy of the IPL and loader software,and partition 2 264-C and partition 3 264-D each contain applicationsoftware and application software information. In some embodiments,partition 2 264-C and partition 3 264-D correspond to the second andthird memory partitions, respectively.

In some embodiments, and as seen in FIG. 9, partition 2 264-C andpartition 3 264-D are each divided into first and second portions. Inthe embodiment depicted in FIG. 9, the first portion of partition 2264-C contains first application software 266 and the first portion ofpartition 3 264-D contains second application software 268. In theembodiment depicted in FIG. 9, the second portion of partition 2 264-Ccontains first application software information 270 and the secondportion of partition 3 264-D contains second application softwareinformation 272. In some embodiments, the application software in caninclude, a datum that can be used to identify/verify the applicationsoftware, such as, for example, a hash or a checksum and informationeither absolutely or relatively identifying the time and/or date thatthe application software was loaded on the blood pump 100.

FIG. 10 is a flowchart illustrating one embodiment of a process 300 foroperation of the blood pump 100 when communication with the systemcontroller 20 is lost or interrupted. In some embodiments, the process300 can be performed on the blood pump 100 and/or by componentscommunicatively coupled to the blood pump 100 such as, for example, theelectronics 130 and/or the control unit 202. The process 300 begins atblock 302 wherein the blood pump 100 is started, and specifically,wherein the pumping of the blood pump 100 is initiated. In someembodiments, the blood pump 100 can be started according to the process220 shown in FIG. 8.

After the blood pump 100 has been started, the process 300 proceeds toblock 304, wherein a control signal is received from the systemcontroller 20. In some embodiments, the control signal received from thesystem controller 20 can be used by the control unit 202 in thecontrolling of the position, motion, and/or performance of the rotor 140of the blood pump 100. The control signal can be received by the controlunit 202 of the blood pump 100, and specifically, in some embodiments,can be received by the communications module 206 of the blood pump 100.

After the control signal has been received, the process 300 proceeds toblock 306, wherein the blood pump operation/performance is matched tothe operation/performance specified by the control signal. In someembodiments, this can include determining the currentoperation/performance of the blood pump 100, comparing the currentoperation/performance of the blood pump 100 to the operation/performancespecified by the control signal, and controlling components of thestator 120 to achieve the operation/performance specified by the controlsignal if the current operation/performance of the blood pump 100differs from the operation/performance specified by the control signal.In some embodiments, the matching of the pump operation/performance tothe operation/performance specified in the control signal can furtherinclude the generation and transmission of a message by the control unit202 to the system controller 20, which message can identify the currentoperation/performance of the blood pump 100.

After the blood pump operation/Performance has been matched to theoperation/performance specified by the control signal, the process 300proceeds to block 308, wherein at least one back-up parameter is stored.In some embodiments, the back-up parameters can include one or severalback-up parameters, and can be stored in the memory 206 of the bloodpump 100. Specifically, in some embodiments, the back-up parameters canbe stored in one of the partitions 264-A-264-F of the flash memory. Insome embodiments, the one or several back up parameters can be receivedas a component of the control signal, in some embodiments, the one orseveral back-up parameters can be created from data received from thecontrol signal, and in some embodiments, the one or several back-upparameters can be received separate from the receipt of the controlsignal. The details of the creation of the one or several back-upparameters will be discussed at greater length below.

After the one or several back-up parameters have been stored, theprocess 300 proceeds to decision state 310, wherein it is determined ifadditional control signals and/or communications from the systemcontroller 20 have been received. In some embodiments, this can includereceiving information from, for example, the communications module 208relating to any received communications. If an additional communicationand/or control signal has been received, then the process 300 returns toblock 306 and proceeds as outlined above.

If no additional control signal and/or communication has been received,then the process 300 proceeds to decision state 312, wherein it isdetermined if the communication time has been exceeded. In someembodiments, the communication time can be, for example, an anticipatedand/or desired frequency with which communications are expected from thesystem controller 20. In one embodiment, for example, the communicationtime can indicate that a communication is expected from the systemcontroller 20 every ten seconds, every five seconds, every second, twicea second, five times a second, ten times a second, and/or at any otheror intermediate frequency.

In some embodiments, the communication time can be the maximum length oftime that can pass without receiving a communication from the systemcontroller 20 before an error is identified and/or an alarm istriggered, in one embodiment, for example, this amount of tune can beone minute, thirty seconds, ten seconds, five seconds, one second, 0.5seconds, or any other or intermediate length of time.

In some embodiments, the properties, of the communication time can beidentified in communication time information stored in, for example, thememory 206 of the blood pump 100. In some embodiments, the communicationtime information is retrieved from the memory, the length of time thathas passed since the last received communication is determined, and thedetermined length of time that has passed since the last receivedcommunication is compared to the communication time, if the length oftime that has passed since the last received communication is less thanthe communication time, then the process 300 proceeds to block 314 andwaits until the end of the communication time. In some embodiments, theprocess 300 then proceeds to decision state 310 and proceeds as outlinedabove.

If it is determined that the communication time has been exceeded, thenthe process 300 proceeds to block 316, wherein the loss or interruptionof communication is indicated. In some embodiments, the loss ofcommunication can be indicated by triggering an error and/or an alarm.In some embodiments, the loss of communication can be indicated by avalue associated with the triggered error and/or alarm, and/orassociated with the loss of communication. This value can be stored inthe memory 206, and in some embodiments, this value can be stored in theRAM.

After the loss of communication has been indicated, the process 300proceeds to block 318, wherein one or several back-up parameters areretrieved. In some embodiments, the one or several back-up parameterscan contain some or all of the parameters contained in the controlsignals received from the system controller 20 and that relate to theperformance of the blood pump 100 including, for example, the speed,operational mode, or pulse parameter of the rotary motor 200. In someembodiments, the one or several back-up parameters can be retrieved fromthe memory 206 such as, for example, the flash memory.

After the one or several back-up parameters have been retrieved, theprocess 300 proceeds to block 320, wherein the wherein the blood pumpoperation/performance is matched to the operation/performance specifiedby the one or several back-up parameters. In some embodiments, this caninclude determining the current operation/performance of the blood pump100, comparing the current operation/performance of the blood pump 100to the operation/performance specified by the one or several back-upparameters, and controlling components of the stator 120 to achieve theoperation/performance specified by the one or several back-upparameters, if the current operation/performance of the blood pump 100differs from the operation/performance specified by the one or severalback-up parameters. In some embodiments, controlling components of thestator 120 to achieve the operation/performance specified by the one orseveral back-up parameters can include generating one or several controlsignals that direct components of the stator to achieve the pumpperformance specified by the at least one back-up parameter.

After the blood pump operation per has been matched to theoperation/performance specified by the one or several back-upparameters, the process 300 proceeds to block 322, wherein a new controlsignal is received. In some embodiments, the new control signal can bereceived from the system controller 20, and can be received whencommunication between the system controller 20 and the blood pump 100 isreestablished. In some embodiments, the new control signal can bereceived at any time. In some embodiments, the time between the controlsignal received in block 304 and the new control signal can be any timelarger than the communication time. In some embodiments, this timebetween the control signal received in block 304 and the new controlsignal can be, for example, 1 second, 5 seconds, 10 seconds, 20 seconds,30 seconds, 1 minute, 5 minutes, 10 minutes, 30 minutes, 1 hour, 1 day,1 week, 1 month, 1 year, and/or any other or intermediate length oftime. In some embodiments, the receipt of the new control signal canlead to the triggering of a return to normal status from the errorand/or alarm state indicated in block 316. In some embodiments, a valuecan be associated with the restored normal state of operation, whichvalue can be stored in the memory 206, and in some embodiments, in theRAM.

After the new control signal has been received, the process 300 proceedsto block 324, wherein the status response is provided. In someembodiments, the status response can be a response indicative of thestatus of the blood pump 100 that can be provided by the blood pump 100to the system controller 20. In some embodiments, the status responsecan include information indicative of the current operation of the bloodpump 100 including, for example, a speed, a mode, or a pulse parameter.

After the status response has been received, the process 300 proceeds toblock 326, wherein the blood pump operation/performance is matched tothe operation/performance specified by the new control signal. In someembodiments, this can include determining the currentoperation/performance of the blood pump 100, comparing the currentoperation/performance of the blood pump 100 to the operation/performancespecified by the new control signal, and controlling components of thestator 120 to achieve the operation/performance specified by the newcontrol signal if the current operation/performance of the blood pump100 differs from the operation/performance specified by the new controlsignal. In some embodiments, the matching of the blood pumpoperation/performance to the operation/performance specified in the newcontrol signal can further include the generation and transmission of amessage by the control unit 202 to the system controller 20, whichmessage can identify the current operation performance of the blood pump100.

FIG. 11 is a flowchart illustrating one embodiment of process 400 forgenerating a back-up parameter. In some embodiments, the process 400 canbe performed as part of block 308 shown in FIG. 10. The process 400 canbe performed by the blood pump 100 and/or components thereof. Theprocess begins at block 402, wherein control signal portions areidentified. In sonic embodiments, the control signal can comprise one orseveral portions which can, in some embodiments, include uniqueinformation. In one embodiment, for example, the control signal caninclude a first portion that can include information relating to a speedof the blood pump 100, and a second portion that can include informationrelating to a mode of operation of the blood pump 100 and/or a pulseparameter of the blood pump 100. In one embodiment, the mode ofoperation of the blood pump 100 can specify pulsatile and/ornon-pulsatile operation of the blood pump 100. In one embodiment, thepulse parameter can specify one of a pulse duration, a systolicpressure, a diastolic pressure, and/or a pulse pressure.

After the portions of the control signal have been identified, theprocess 400 proceeds to block 404 wherein the back-up parameter isextracted from, for example, the control signal. In some embodiments,the extraction of the back-up parameter can include the separation ofone of the portions of the control signal from the other of the portionsof the control signal. In one embodiment, the back-up parameter cancomprise the first portion of the control signal, which first portionincludes information relating to the speed of the blood pump 100.

After the back-up parameter has been extracted from the control signal,the process 400 proceeds to block 406, wherein the back-up parameter isstored. In some embodiments, the back-up parameter can be stored in thememory 206, including, for example, in the flash memory or in one of thepartitions of the flash memory. After the back-up parameter has beenstored, the process 400 proceeds to block 408 and continues with block310 of FIG. 10.

In the foregoing specification, the invention is described withreference to specific embodiments thereof, but those skilled in the artwill recognize that the invention is not limited thereto. Variousfeatures and aspects of the above-described invention can be usedindividually or jointly. Further, the invention can be utilized in anynumber of environments and applications beyond those described hereinwithout departing from the broader spirit and scope of thespecification. The specification and drawings are, accordingly, to beregarded as illustrative rather than restrictive, It will be recognizedthat the terms “comprising,” “including,” and “having,” as used herein,are specifically intended to be read as open-ended terms of art.

What is claimed is:
 1. A mechanical circulatory support systemcomprising: a controller configured to generate control signalscomprising at least one performance parameter and to repeatinglytransmit the control signals within consecutive time periods; and animplantable blood pump communicatively coupled to the controller, theblood pump comprising: a rotary motor; and a control unitcommunicatively coupled with the rotary motor and configured to: receivethe control signals from the controller; track the consecutive timeperiods; and retrieve at least one back-up parameter if a control signalis not received from the controller within a predetermined time ornumber of the consecutive time periods to ensure operation of theimplantable blood pump during a communication interruption or loss. 2.The mechanical circulatory support system of claim 1, wherein thecontrol unit is further configured to control at least one of the motionand position of the rotary motor.
 3. The mechanical circulatory supportsystem of claim 1, wherein the control unit is further configured tocontrol the speed, mode, or pulse parameter of the motor according tothe received control signals or the at least one back-up parameter. 4.The mechanical circulatory support system of claim 3, wherein thecontrol unit is further configured to: determine a current pumpperformance; compare the current pump performance to the at least oneback-up parameter; and generate control signals to achieve the pumpperformance specified by the at least one back-up parameter.
 5. Themechanical circulatory support system of claim 1, wherein thepredetermined time comprises at least 5 seconds.
 6. The mechanicalcirculatory support system of claim 1, wherein the consecutive timeperiods have a length of time of less than 1 second.
 7. The mechanicalcirculatory support system of claim 6, wherein the predetermined numbercomprises at least five consecutive time periods.
 8. The mechanicalcirculatory support system of claim 1, wherein the at least oneperformance parameter comprises at least one of a pump speed, a pumpoperational mode, and a pulse parameter.
 9. The mechanical circulatorysupport system of claim 8, wherein the pulse parameter comprises one ofa pulse duration, a systolic pressure, a diastolic pressure, and a pulsepressure.
 10. The mechanical circulatory support system of claim 8,wherein the pump operational mode comprises at least one of continuousspeed, pulsatile pumping, or non-pulsatile mode.
 11. The mechanicalcirculatory support system of claim 1, wherein the at least one back-upparameter comprises at least one of a pump speed, pump operational mode,and a pulse parameter.
 12. The mechanical circulatory system of claim11, wherein the control unit is configured to generate the at least oneback-up parameter from the control signal received from the controller.13. The mechanical circulatory system of claim 12, wherein the controlunit comprises memory which stores the at least one back up parameter.14. The mechanical circulatory support system of claim 1, wherein thecontrol unit is configured to return to operation based on controlsignals received from the external controller when communication isre-established.
 15. The mechanical circulatory support system of claim1, wherein the controller comprises an external or implantablecontroller configured to wirelessly transmit the control signals. 16.The mechanical circulatory support system of claim 1, wherein thecontroller comprises an external or implantable controller having adriveline coupled to the implantable pump to transmit the controlsignals.
 17. The mechanical circulatory support system of claim 1,wherein the control unit is configured to control the mode of the rotarymotor according to the received control signals or the at least oneback-up parameter.
 18. The mechanical circulatory support system ofclaim 1, wherein the control unit is configured to control the pulseparameter of the rotary motor according to the received control signalsor the at least one back-up parameter.
 19. An implantable blood pumpcomprising: a rotary motor; a control unit communicatively coupled withthe rotary motor and configured to: repeatingly receive control signalscomprising at least one performance parameter; track receipt of thecontrol signals over a time period; and retrieve at least one back-upparameter if a control signal is not received within a predeterminedtime period to ensure operation of the implantable blood pump during acommunication interruption or loss.
 20. The implantable blood pump ofclaim 19, wherein the control unit is configured to provide a statusupdate in response to a received control signal.
 21. The implantableblood pump of claim 19, wherein the at least one back-up parameter isretrieved if a control signal is not received within the predeterminedtime period of 5 seconds.
 22. The implantable blood pump of claim 19,wherein the at least one performance parameter comprises at least one ofa pump speed, a pump operational mode, and a pulse parameter.
 23. Theimplantable blood pump of claim 22, wherein the pulse parametercomprises one of a pulse duration, a systolic pressure, a diastolicpressure, and a pulse pressure.
 24. The implantable blood pump of claim22, wherein the pump operational mode comprises at least one ofcontinuous speed, pulsatile pumping, non-pulsatile mode.
 25. Theimplantable blood pump of claim 22, wherein the at least one back-upparameter comprises at least one of a pump speed, a pump operationalmode, and a pulse parameter.
 26. The implantable blood pump of claim 22,wherein the control unit is configured to return to operation based oncontrol signals received from the controller when a new control signalis receive.
 27. The implantable blood pump of claim 22, wherein therotary motor is located within a first implantable housing and thecontrol unit is located in a second implantable housing.